1. Field of the Invention
The present invention relates to a personal station (PS) that detects the present location and performs navigation corresponding to cell station numbers and control carriers or communication carriers of a personal handyphone system (PHS).
2. Description of the Prior Art
A location information detecting system for use with a PHS has been proposed. FIG. 6 shows an example of the construction of the proposed location information detecting system. In FIG. 6, reference numeral 600 is a personal station (hereinafter referred to as a PS). Each PS is designated a unique PS number. Reference numeral 601 is a cell station (hereinafter referred to as a CS). CSs are disposed at intervals of around 100 meters. Each CS is designated a unique CS number. Reference numeral 602 is a visited mobile service switching center (referred to as a visited-MSC) that controls connections of incoming calls and outgoing calls in a radio region. Reference numeral 603 is a visitor location register (hereinafter referred to as VLR) that stores location information and so forth of a PS that is present in a visited-MSC. Reference numeral 604 is a home location register (hereinafter referred to as an HLR) that stores subscriber information, location information, and so forth. A plurality of CSs 601 are connected to a visited-MSC. An area managed by the visited-MSC is referred to as a simultaneous paging area.
Next, the method for registering the location information of the present location of a user with a PS 600 will be described with reference to FIGS. 6 and 7. FIG. 7 is a flow chart in the case that the user initially registers the location information to the VLR 603 of the PS 600. At step 700, when the user moves and thereby the simultaneous paging area of the user varies or when the user requests the CS 601 to register the location information, a signal for registering the location information is transmitted from the PS 600 to an adjacent CS 601. This signal is automatically or manually transmitted.
When the signal is transmitted at step 700, the flow advances to step 701. At step 701, a radio communication link is established between the CS 601 and the PS 600. Thereafter, at step 702, the PS 600 sends a location information registration request signal to the CS 601. The location information registration request signal is sent to the visited-MSC 602 through the CS 601. At step 703, the visited-MSC 602 determines whether or not the PS 600 that has sent the request signal is a subscriber of the system corresponding to subscriber information stored in the HLR 604. When the PS 600 is a subscriber of the system, at step 704, the PS number included in the location information registration request signal received from the PS 600 is stored in the VLR 603. Thus, the location registration process is completed.
It should be noted that a system that performs the function of the VLR with the HLR is possible. In addition, to register more precise location information, a CS number designated to each CS may be stored in the VLR.
In such a system, when the PS with a subscriber number accesses the VLR (or the HLR), the PS can detect the area thereof the PS. However, so far, the function of allowing the PS to actively detect its location using the PHS has not been proposed. Thus, in the conventional system, the user only obtains information of which the user is present in the vicinity of a CS.
In the conventional location information detecting system, the VLR (or HLR) stores at most visited-MSC numbers (or cell station numbers) as location information. Thus, the user cannot obtain the moving direction of the PS.
Therefore, an object of the present invention is to provide a personal station that can precisely detect the location thereof.
Another object of the present invention is to provide a personal station that can also detect the moving direction thereof.